This invention relates generally to a fluid temperature control system for cooling a heat generating portion by fluid to effect a temperature control, and more particularly to a fluid temperature control system for effecting precise temperature control, for example, in order to cool a computer, and also to a computer system using such control system.
In a conventional apparatus as disclosed in Japanese Patent Unexamined Publication No. 56-157745, a plurality of refrigerators are provided, and the temperature of water fed through a main feed pipe, temperature at an inlet of each of the refrigerators and the flow rate of the circulating water through a main return pipe are detected. The inlet temperature of each refrigerator is compared with a set temperature, using a computer, and the number of the refrigerators to be operated is controlled or determined, thereby controlling the temperature of the water circulating through a heat generating portion.
In a system disclosed in Japanese Patent Unexamined Publication No. 56-24622, a power source for a computer is turned on, and a constant-voltage/constant-frequency power source is operated under the control of a controller. After the operation of the latter power source becomes steady, the operation of an air conditioner is started, and after temperature and moisture conditions become constant within predetermined ranges, the power source for the devices constituting the computer system is turned on. However, in such conventional systems, no means are provided for rapidly controlling the fluid temperature to the set temperature when starting the operation and, since the temperature of the circulating water is controlled by changing the number of the refrigerators to be operated, the water supplied to a heat generating portion is subjected to large temperature variations; and the starting and the stopping of the refrigerators must be done frequently. Therefore, it has been desired to rapidly control the fluid temperature to the set temperature so as to bring the computer into a usable condition in a short time, thereby enhancing the efficiency of its use; to precisely control the fluid temperature to the optimum temperature for operating LSI chips in a stable manner; and to improve the reliability of the system.